Process of coating paper containers.



E. Cn HAWKINS. PROCESS or COMING PAPER CONTAINERS.

, APPLICATION FILED JULY 6.191-8. 1,391 98411, Patented Apr. 29,1919.

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lspecication'of Letters Patent. Patented kpll. 29, llllllll@V Application led 3111576, 1918. Serial No. 243,686.

Toall wiz/m z ''vmayconcerm i Be it known that li, EDWIN C. HAWKINS,

a citizen of the United States, residing aty v cally with broken joints,` and where the ends of the tube are provided with separate end 'members for closing such ends.

s Many articles must not only be protected while in storage or transit, but must be kept free 'from moisture, because they would be damp. Containers of the mailing tube type have not heretofore been suitable for such articles, for attempts e'ectively to waterproof Asuch containers, against submergence for instancehad not been successful. This was largely because of the joints in these containers, both between the adjacent'turns of the helical winding and between the body vbf the container and its end pieces, which Y joints gave water ready access to the edges of the paper layer so that it could soak edgeof the strucwise through them. By reason ture of the paper used for such tubes, such as strawllioarcl and `test board, this is much easier than soaking vtransversely therethrough.

By my present invention, l not only make the paper container impervious to water transverselybut also water-prooi:l thejoints both in the body of the container and between such body and theendl pieces, thus preventing access 'of water to the edges of the paper layers.l l do this by applying a solution of rubber in some volatile solvent over the surface of the container, and most particularly over the joints, permitting the solvent to evaporate to leave a thin lm ot rubber over the surface to which the solution 1s applied, then preferably applyin a second coat ot the same solution and a lowing its solvent to evaporate, and then vulcanizing the rubber iilm in position on the4 surface of the container and over the joints thereof. The' article, the waterproofed paper container, which is. produced by thus process, 1s

Aclaimed in my co-pending application Ser.`

No. 243,685, of even tiling date herewith.

The accompanying drawing illustrates my invention. Figure 1 is a perspective View of a waterproof paper container which has been Water-proofed in accordance withmy inven-` tion; and Fig. 2 is av partial longitudinal section through such a paper container, olf

somewhat different form and on a somewhat larger scale, and with the thickness of thev walls and therubber coating magnified, to show more clearly how7 the rubber coating overlaps the joints. l

'The body of the containercomprises'a plurality of layers 10, of suitable paper such as strawboard or test-board, wound helically upon one another to form a* tube, in the usual manner of mailing tubes.y The joints 1l of the successive layers break with one another,

so that beneath such joints of each layer there is a jointless surface of the adjacent layer. rlhe end members of the tube fit over `or within the tube, as. desired, in the latter case some of the outer layers of the tube near the end preferably being folded in. upon themselves so as to leave no raw edges exposed. The end pieces may be of material similar to that of the tube, as is the permanently closing end disk 12 of Fig. 2; or may be of metal, as are the end pieces 13 of Fig.

2 and the end bands 14 and 15 of Fig. l. if of metal, they may be parts of closing end caps, as in the band 14; or they may or may not be provided with internal or external screw threads, as are the end piecel and the end band 15, for receiving a detachable closing piece, such as the end cap 16 of Fig. 1. In the particular containers shown, apaper closing disk is shown inserted in one end ofthe container body of Fig. 2, and metal end caps or bands are shown encircling the other end ofthe container in that figure and both ends of the container` in Fig. 1; but these are merely illustrative arrangements, to show both an inserted and an encircling end piece and both a paper and a metal end piece, and neither arrangement is essential. rll`he paper container itself is old, and may take various forms; per, se, it is not my invention.

ln order to water-proof the container, l first apply to one or both surfaces-as illustrated, to the outside suriace-a solution of rubber in some volatile. solvent, such as benzol, gaso'lene, carbon tetra-chlorid, or'carbon container and the end pieces 12, 13, 14, or l 15. When the end pieces-are paper, such as the disk 12, I apply the solution over the corresponding surface thereof as well as over the entire surface of the tube; and when they are metal, such as the end piece 13 and the j end bands 14 and 15, I apply lthe solution over the joints 17 and part way up onto the metal. Preferably I apply this solution with a brush, brushing in both directions;- and particularly- I brush in both directions over the helical joints 11 so as to cover both raw edges at suchjoints. I find the best results are obtained if the brushing over the joints 11 is done obliquelyt'o such joints, as by brushing in planes perpendicular to the tube axis. After the solution has Abeen applied, the solvent ispermitted to evaporate, preferably in a current of hot air to ex edite the evaporation. Thisleaves a rst t in film of, rubber on the surface to which the solution was applied and spanning the joints 11 and 17 This first coat acts as a filler, to some extent, to fill the pores of 'the paper. After'the solvent of the rst coat has evaporated, a second coat ofthe rubber solution is applied over the first coat, care being taken as before to cover the joints 11 and 17; and thenl the `solvent `of this second coat is allowed to evaporate. This leaves a second I rubber film superposed upon and coalescing with the first, to form a rubber coati 18 covering and s anning the joints 11 a 17. Then this rubber coating 18, if obtained from a nonvulcanizing solvent such as gasolene, benzol, or carbon tetrachlorid, is exposed to a suitable vulcanizer, such as sulfur chlorid. rlhe vulcanizer may be applied with a brush as a liquid, or the rubber coating may be exposed to the fumes of the vulcamzer. "The vulcanizing process is continued until the desired quality of rubber in the coating is obtained. However, if the rubber solvent used is itself a vulcanizer,

vulcanization is produced thereby, and no 4 other vulcanizer need be applied.

rllie rubber solution and the vulcanizer may be applied by hand or by machinery, one machine for applying them to openended tubular containers being shown in the co-pending1 application of Charles B. Macy, Ser. No. 243,629, of even filing date herewith. This produces a contain r which is substantially water-proof under rigid tests. It may be submerged'in water under considerable pressure or considerable lengths of time, without any seepa e of moisture through it. It may there ore be used for storing and Atrans orting materials which must be kept dry ut which are in danger of exposure to moisture in storage or trans sit; such as gun shells, shell'timers, medical and surgical and hospital supplies, and also many other articles useful in both War and peace. The container may also be used as the ermanent casing of many articles, such for instance as hand grenades, the contents of which must be kept dry. By applying the rubber solution-to t c inside surface, instead of to the outside surface, the container is protected from internal moisture, so that it may be used as a holder for such liquids as u do not re-act uponor dissolve rubber'.

I claim as my invention:

1. The'process of water proong a paper container having joints in its surface, which consists in applying over .the joints in the surface of su container a solution of rubber in a volatilev'solvent, permitting the solvent to evaporate to leave a film of rubber spanning such joints, and yvulcaniziiig such film of rubber.

2. The process of water proofing a paper container having joints in its surface, which consists in applyingvto the surface of such container and over the joints in such surface a solution of rubber in a volatile solvei'it,.perv mitting the solvent to evaporate tol leave a film of rubber covering such surface and spanning such joints, and vulcanizing such lm of rubber. E

3. -The process of water proofing a paper container having joints in its surface, which consists in applying over thev joints in the surface of such container by brushing1 in both directions across such joints in lines oblique to such joints a'solution ofrubber in a volatile solvent so as to cover the raw edges at such joints, permitting the solvent to evaporate to leave a film of rubber spaniut ning-'such joints, and'vulcanizing sucliA lm j of rubber.

4. The process ofwater--proong a paper A container having joints in its surface, which consists in applying over the joints in the sul'- face of such container by brushing in both directions across such joints a solution of rubber in a volatile solvent so as to cover the raw edges at such joints, permitting the solvent to evaporateto leave a film of rubber spanning such joints, and vulcanizing such film of rubber.

Inwitness whereof, I have hereunto set my hand at Indianapolis, Indiana, this 21st day of June A.. D. one thousand nine hundred and eighteen.

.EDWIN o. HAS. 

